Question

Solve for the variable. a + 5.1 = 10.9
A. 5.8
B. -5.8
C. 16
D. -16

Answer 1

a=5.8, or A

Answer 2

The best way to think of these problems is to say "What plus 5.1 =10.9"

You can try a few different of the options. will 16 + 5.1 = 10.9? No, so that can't be it.

If you go through the options, you'll see A, 5.8, is the only one that fits.

Answer 3

Is there anything you're having trouble with in specific with these problems? You can think of the a as a question mark ? if it makes it easier.

Answer 4

Or because you see that the problem is +5.1 and you're trying to get a isolated on one side. To do this you must undo the +, so you must -.

So
a+5.1=10.9
-5.1. -5.1
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a=? , which is whatever 10.9-5.1 is